1. Field of the Invention
This invention relates in general to gas furnaces and, in particular, to an inducer utilized to aid the flow of flue gas through the heat exchanger cells of a gas furnace. More specifically, but without restriction to the particular embodiment hereinafter shown and described, this invention relates to a snap and lock feature allowing expedited assembly of the inducer cover and housing.
2. Discussion of the Background Art
Gas furnaces typically include a primary heat exchanger positioned adjacent a burner box containing burners. During operation of the furnace, a blower moves circulating air over the heat exchanger to produce heated air that is directed to a desired location. Gas is supplied to the burner box by a gas manifold having orifices that direct the gas into the burners. The gas exiting the burners is ignited by an ignitor provided in the burner box. The burners allow combustion of the gas as well as direct heated flue gas into the heat exchanger. The typical heat exchanger includes cells with a channel or pass formed in each cell to direct the flow of flue gas produced by combustion. These cells are positioned side by side in a parallel manner and are provided with a predetermined spacing to allow the blower air to flow around the cells. The blower air is thus heated by convection as it circulates over the cells.
A sheet metal panel or cell panel having burner target plates is typically provided to position the burner box relative to the inlet side of the cells contained in the heat exchanger. An inducer having a motor and fan is typically mounted on the discharge side of the heat exchanger. The inducer is activated to induce a flow of flue gas through the heat exchanger and into vent piping so that the flue gas may be vented to a location exterior to the furnace.
The residential heating industry has advanced with the advent of condensing gas furnaces. These furnaces typically included a primary heat exchanger as well as a condensing heat exchanger. A blower in these condensing furnaces similarly provides circulating air flow over both heat exchangers to produce heated air that may be directed to a desired location by a system of duct work and registers.
In such condensing furnaces, both the primary heat exchanger and the condensing heat exchanger include cells with a channel or pass formed therein to direct the flow of flue gas produced by combustion. These cells in both the primary and secondary heat exchangers are positioned side by side in a parallel manner and are provided with a predetermined spacing to allow blower air to flow around both groups of heat exchanger cells. Gas is similarly provided to the condensing furnace by a gas manifold having orifices that direct the gas into burners contained in a burner box. The burner box is secured to the inlet side of the primary heat exchanger to align the discharge end of the burners with the inlet ports of the primary heat exchanger cells. The gas is ignited by an ignitor as it exits the burners contained in the burner box. The heated flue gas produced by combustion is then directed into the primary heat exchanger cells.
The condensing heat exchanger of the furnace is configured in a similar manner to its primary heat exchanger. A series of side by side condensing cells is provided. Each of these condensing cells has an inlet port for receiving flue gas discharged from the primary heat exchanger. The inlet ports of the condensing heat exchanger cells are aligned and secured in a sheet metal panel forming the inlet side of the condensing heat exchanger. The inlet side of the condensing heat exchanger is fluidly connected to the discharge side of the primary heat exchanger by a coupling box. The condensing cells function to exchange heat with the clean circulation air and to condense water vapor out of the products of combustion contained in the flue gas. This condensate drains from the condensing cells into a collector box provided on the discharge side of the condensing heat exchanger. The collector box extends through the cell panel below the burner box and includes tubing to further drain the condensate from the box into drain piping. The collector box is provided with an opening to which the intake side of an inducer in fluidly secured. The inducer in the condensing furnace induces the flow of heated flue gas through the cells in both the primary and condensing heat exchangers.
With recent advancements in the art, a commercially feasible condensing gas furnace having four possible installation orientations has been proposed by the assignee of the present invention. Such gas-fired furnaces are known in the art as multi-poise condensing furnaces and are disclosed, for example, in the co-pending, commonly assigned U.S. patent application Ser. No. 08/089697, entitled "Multi-Poised Condensing Furnace". These multi-poise furnaces are installable with either an upflow, downflow, horizontalright flow, or horizontal- left flow orientation. They include design features which allow the furnace to function properly and just as efficiently in any one of these four possible installation orientations. One such feature results in proper drainage of condensate from the condensing heat exchanger cells into the collector box irrespective of the selected installation orientation. As another example, the inducer, employed to accommodate the multi-poise furnace, features two optional discharge ports. Depending on the installation orientation, one of the two inducer discharge ports is selected to be connected to the vent piping while the other unused port is capped with an air-tight seal.
All of the above discussed furnaces typically rely on an inducer for proper operation. The typical inducer includes a housing provided with an intake port that is fluidly connected to the discharge side of a heat exchanger and a discharge port for venting the flue gas. The inducer also includes a cover having a motor mounted on one side with a shaft extending through the cover to the other side. The end of the motor shaft is supplied with a circular fan. The cover is typically secured to the housing by screws. This manner for assembling together the inducer housing and cover is relatively expensive, requires a relatively long period of assembly time, and may result in uneven or excessive pressure around a sealing gasket provided between the housing and cover.